Several symptoms that characterize Major Depressive Disorder (MDD), including hypersomnia, psychomotor retardation, and decreased engagement in pleasurable activities, involve withdrawal from environmental stimuli. These withdrawal behaviors are thought to contribute to the maintenance of depression by reducing opportunities for contact with positively-reinforcing activities and situations. Psychotherapies for depression that target behavioral withdrawal by focusing on increasing behavioral activation have shown efficacy comparable to other empirically-supported therapies (e.g., cognitive therapy) in randomized controlled trials. However, as with other therapies, a sizable proportion of depressed patients receiving behavioral activation therapy (BA) do not improve, or improve but do not attain remission, a finding that points to the need to investigate methods for improving rates of treatment success. Psychophysiological evidence suggests that asymmetric cortical activity - specifically, greater right-than-left frontal activity as measured by electroencephalography (EEG) - may underlie the behavioral withdrawal seen in IVIDD, and that manipulating this asymmetry with EEG biofeedback can alter emotional responses in nondepressed samples. The proposed study therefore will integrate these psychosocial and psychophysiological approaches to the treatment of MDD. Using a randomized control design, this study has the goal of assessing the preliminary efficacy of a combined treatment for MDD, to determine if the efficacy is sufficient to warrant a larger clinical trial. To meet this goal, this study has two specific aims: (1) to augment the efficacy of BA for MDD through the concomitant use of an EEG biofeedback procedure that alters the alpha asymmetry pattern seen in depression, with BA expected to be more efficacious for individuals whose left- relative-to-right cortical activity is increased with biofeedback than for individuals who receive a placebo biofeedback procedure;(2) to examine potential mediating and moderating influences on this effect, with the effect expected to be mediated by changes in approach and withdrawal motivation, and moderated by individual differences in magnitude/direction of baseline asymmetry and level of withdrawal orientation in depression symptoms. PUBLIC HEALTH RELEVANCE: If successful, these findings would have translational value, providing a method of ombining treatment modalities that leads to symptom relief for a greater number of people than can currently be achieved with the use of psychotherapy alone. Moreover, it would establish a physiological treatment component that is both inexpensive and noninvasive compared with other available physiological treatments for depression.